EDIT 2014-10-20
Soundclip added. Clean sound running through the parallel Universe (nothing inserted in the send/return).

here is a cool circuit that reminds me of Tim Escobedo's Uglyface. It does heavy fuzz, oscillation and crazy synthy octaveish glitchy sounds.

Note that the send and return needs to be connected if you are not using other pedals through the Parallel Universe's effect loop. The easiest way would be to use a switched jack for the send and connect the switched lug to the input on the return jack. Or simply just omit the send and return and have them connected in the box. But it's when using other pedals through the fx loop you get really crazy sounds... :)

Here's a very cool synthy sounding octave down / up invented by Slacker (the creator of The Echobase). Original thread here. I included the Octave up addon from the schematic aswell. I had to use shitloads of cuts and links in this layout, but at least I got it into a good size. :)

I did have problems getting this one to work/track properly. Only the low E and A strings tracked and I had to hit the strings hard. Here is what I did... Probably not the best solution lol, but for now it's good enough until I have more time to try out other things. If you want to build it 1:1 with the schematic, just omit the 47K resistor. Here's a short soundclip of the circuit/layout (with my fix):

I'm using humbuckers, neck pickup, mix at 50%, Octave up maxed and 2nd octave down selected.

Here's one insane fuzz/noise machine invented by Anchovie at the diystompboxes forum (original thread here). Have a look at my completed build here.

Here's an interesting fuzz if you like noise :)

I found that a B100K works better for Oscillation Frequency and A20K for Power Starve.

Here a demo-video I found on youtube